The Rim wildfire burning near Yosemite National Park is huge and frightening. More than 100,000 acres in steep, difficult terrain have been burning - and as of Friday evening, most of it was still out of control.

Groveland, a town of about 600 people, is just a few miles from the fire and has been nearly emptied of visitors. The fire has threatened about 4,500 homes.

While the fire isn't yet threatening Yosemite Valley, its proximity and obvious danger offer a contrasting, and sobering, reminder of the power of nature.

It's also a reminder of how dependent San Francisco is on that area for both water and power.

The city owns three powerhouses and about 20 miles of electricity transmission lines within the fire zone. Those powerhouses provide 100 percent of the electricity to power San Francisco's municipal buildings, including the airport - and two of them are currently out of commission. The city has been purchasing energy on the open power market to make up for the loss. It's fortunate that San Francisco already had a contingency plan in place for this possibility, as there hasn't been such a serious wildfire in that area for quite some time.

San Francisco also has a contingency plan in place for its water supply should Hetch Hetchy (which provides 80 percent of the city's drinking water) have trouble, but as of press time the reservoir was up and running. San Francisco Public Utilities Commission spokespeople assured us that the water supply is being carefully monitored for any problems, like the presence of ash. Five San Francisco fire strike teams are also in the Yosemite area, helping to battle the fires.

It's unclear what all of this will cost, as the fires still burning. San Francisco is counting on some reimbursement for its costs from the state and federal governments, which brings up a thorny question: Is the federal government going to update its firefighting funds to reflect the modern realities of climate change?

Many experts believe wildfires are only going to get worse in the years to come, particularly in the western U.S. Yet for the second year in a row, the federal government has already exhausted its budget for fighting wildfires and will be forced to cover the rest of fire season by moving funds from other sources, including fire prevention. Wildfires have become more and more prevalent since 1985, but instead of planning for that reality, Congress has ignored it.